"The disappearance of this habitat could be detrimental to our nation's seafood supply.” - NOAA assistant secretary Mark Schaefer

The loss of Gulf of Mexico saltwater wetlands more than doubled between 2004 and 2009 when compared to an earlier five-year period, a federal report released on Thursday said. The rising rate contributed to the Gulf Coast accounting for 71 percent of wetlands lost across the contiguous United States from 2004 to 2009.

Saltwater wetland losses in the Gulf of Mexico largely were attributed “to the effects of severe coastal storms such as Hurricanes Katrina and Rita in 2005 and Hurricane Ike in 2008, which inundated wetlands with storm surge, abnormally high tides, increased rainfall, runoff, increased sediment and debris deposition and erosion,” according to the report.

The study also pointed to the adverse affects of oil and gas development, “which has increased the vulnerability of these wetlands to climate related changes," including stronger hurricanes and other coastal storms.

The previous report, released in 2008, largely attributed Gulf wetland losses to development and other human activities.

About 257,150 acres of total wetland loss was recorded along the Gulf Coast between 2004 and 2009, according to the recent study. The report also tracked losses along the Pacific and Atlantic coasts, as well as the Great Lakes shorelines.

View full sizeGraphic of wetland gains and losses in coastal watershed of each coastal region between 2004 and 2009 as a part of the report released on Thursday.

It found that in 2009 there were an estimated 41.1 million acres of wetlands in coastal watersheds. Between 2004 and 2009, wetland area in the coastal watersheds of the United States declined by an estimated 360,720 acres.

In addition to the Gulf Coast losses, the report stated that the Atlantic Coast lost 111,960 acres and the Pacific Coast lost 5,220 acres.

The report concluded that more than 80,000 acres of coastal wetlands were being lost on average each year, up from 60,000 acres lost per year during the previous study that examined the period between 1998 and 2004.

“Wetlands are important to our nation’s heritage, economy and wildlife – especially when it comes to coastal communities,” Jewell said. “When a study shows that an area four times the size of Miami is disappearing every year, it underscores the importance of strengthening our collective efforts to improve wetlands management, to reduce losses and to ensure coastal infrastructure and resources are protected.”

Saltwater wetlands declined by an estimated 1.5 percent across the study area. That’s a 35 percent increase over the rate of saltwater wetland loss reported in the previous 5-year study.

The increased loss rate in the nation was attributed to accelerated losses in the Gulf of Mexico.

In terms of the Gulf Coast losses, the studies authors stated that about one third of them were from Louisiana, but they added that the study did not looks at specific trends for individual states.

View full sizeGraphic of coastal watersheds of the upper Gulf of Mexico that shows the magnitude of saltwater (intertidal) wetland loss to open water, 2004 to 2009, as a part of the report released on Thursday.

The findings also noted large loss of freshwater, forested wetland areas attributed to urban and rural development and some forestry practices.

The report also noted that in some coastal watersheds, rising ocean levels are encroaching into wetlands from the seaward side, while development from the landward side takes a further chunk out of the existing wetland area and prevents them from being able to migrate inland. That dual threat could squeeze wetlands into an ever smaller and more fragile coastal fringe, according to the report.

“In addition to the important economic and safety benefits they provide to people, coastal wetlands are also vitally important to native fish and wildlife species,” said U.S. Fish and Wildlife Service Director Dan Ashe. “While they comprise less than 10 percent of the nation’s land area, they support 75 percent of our migratory birds, nearly 80 percent of fish and shellfish, and almost half of our threatened and endangered species.

“We can’t sustain native wildlife for future generations without protecting and restoring the coastal wetlands that support them.”

Mark Schaefer, the National Oceanic and Atmospheric Administration’s assistant secretary for conservation and management, pointed to the effects fisheries losses can have on coastal economies.

“The three most valuable species that depend on habitats supported by our wetlands—crab, shrimp, and lobster— had a combined value of $1.6 billion in 2012," Schaefer said."The disappearance of this habitat could be detrimental to our nation's seafood supply.”

In additional to the Gulf Coast losses, the report stated that the Atlantic Coast lost 111,960 acres and the Pacific Coast lost 5,220 acres.

Although the losses along the Pacific Coast were small in comparison to the others, the study noted that they represent an important component of coastal wetlands in that region, which has a predominantly high, rocky coastline.